Radio frequency identification (RFID) is a technology which is rapidly gaining acceptance in a variety of fields including warehousing, inventory management, and product tracking. It is based on a system which is comprised of a reader (e.g., a radio transmitter/receiver with antennae), a tag (comprised of a miniature antenna with a silicone chip attached thereto), and a processor which captures information received from individual tags. Each silicone chip is programmed with a unique electronic product code (EPC), and in many instances tags are covertly attached to or packaged with products, for example via a blank or printed label or by some other means.
Readers generally operate at three different frequencies: low, high, and ultra high (ultrahigh being generally recognized as being from 300 to 900 MHz). The read range of a tag is a function of the frequency and size of the tag antenna, because tags are passive and are only energized when they are in the field of the radio waves transmitted by the reader. The ultra high frequency (e.g., 900 MHz) tags are becoming the tag of choice for most inventory control applications because of their relatively long read range (e.g., up to 14 feet in typical situations, and up to 30 meters in some applications).
Ordinary labels are relatively inexpensive to produce (e.g., less than a penny each), as compared to the cost of producing an RFID tag (e.g., $0.20 to $1.00 or more each), even before it is applied to a printed label. For this reason, RFID labeling has been generally restricted to the shipping carton or skid level. However, now there are powerful forces which are mandating RFID tagging at the item level for some products. Various governmental agencies, such as Congress, the Department of Defense and the FDA are pressuring parties, such as suppliers and pharmaceutical companies, to create better inventory control of certain goods, materials, and prescription drugs, and to implement more effective product authentication through overt and covert security features. In addition, Wal-Mart® has dictated to its major suppliers that they will support RFID within the very near future.
Currently, RFID tag manufacturers are not able to guarantee that all tag inlays that they ship are readable, functional tags—in fact, as many as 20% of the incoming tags may be non-readable. However, for many applications, label printers must be able to ensure that 100% (or at least very close to 100%) of the RFID labels are readable. This means that all RFID labels need to be read and verified when they are in their finished state, i.e. mounted in close proximity to one and another (e.g., inches apart) in a continuous web of paper which is then coiled into a roll of labels. Reader/verification equipment exists that at slow speed can read labels which are close together with a very short read range. Similarly, reader/verification equipment exists that can read RFID labels which have a longer read range (e.g., several feet), but the labels have to be far apart. The difficulty is in discriminating between labels that have a long read range, but that are spaced closely together. There is no known commercially available system which will effectively guarantee that substantially 100% of the ultra high frequency (e.g., 900 MHz) tags mounted in a roll at close proximity (e.g., a few inches apart) and that have a long read range (e.g., greater than 24″) are all functional tags, while being processed at normal production speeds (e.g., several hundred labels per minute).
What is desired, therefore, is a system and method for validating radio frequency identification tags to ensure proper functioning thereof which is capable of ensuring that 100% (or at least very close to 100%) of the RFID labels are readable, which is capable of reading and verifying RFID labels when they are in their finished state, i.e. mounted in close proximity to one and another (e.g., inches apart) on a liner or carrier (for example a continuous web of paper of the like), which is adapted to be used in conjunction with tags having a long read range (e.g., greater than 24″), and which is capable of reading and validating labels moving at a relatively fast speed.